wireless printing

Ok I have a question. Im a Realtor and I am the supposedly “tech savy” person in our office but I need help. Im trying to help a fellow Realtor set up a wireless printer. We have a wireless network set up for our whole office already (the router is in the basement), and he has his printer (which is wireless ready) hard wired to his laptop in his office, but he wants to allow his assistant to print from his printer also from another office across the hall. How or can we get his printer to pick up his assistants laptop across the hall? Any suggestions or help would be greatly appreciated. Thanks!

jonathan